This is a parody of J. Austin Wilde's Essay on Battle Choreography.
I recommend reading it first before criticizing my choice of words.

[Parody]:  Lemon Choreography

One of the hardest parts of writing a lemon story is the sex scene.
Be it man on top, with toys, or in bathtubs, I always hear from other
authors about the difficulty they have in writing a good sex scene. I
enjoy writing sex scenes, but nevertheless, I too stress over a good
lemon sequence.

I think we can all agree that the worst thing to do is write a grunt by
grunt account of what is transpiring. This is dry and uninspiring. Sex
scenes are meant to evoke an intense experience in the reader, not bore
him to sleep. With that said, I'll move on to things I put in practice
in my own scenes. Writers are all different, with varying messages to
convey to the reader, so some of what I will write below some may not
agree with. Take it with a grain of salt, this is what works for me.

I classify sex into three levels of interaction: physical, emotional,
plotwise. We can extend any of these into a larger scale orgy,
but for now let's concentrate on sex between individuals or small
groups.

1. Physical interactions can be the most personally challenging, and I
find it is the type most authors have problems writing. Simply put, 
physical relations are the raw physical exchange of fluids using one's own
body or a weapon as an extension of one's own body. It involves direct
action with the human body. Physical relations are the most intense type
of sex for the character involved. A good way to intensify sex to
a reader is to personalize a sex between your character and his
opponents. Describe what the characters see, hear, feel, or even
smell. Describe his physical state as they perform. Above all, as Redneck 
so wisely said, use action words frequently. 

I hate to say it, but having even a basic familiarity with marital arts
and the principles they are founded on will do wonders for your
choreography. This doesn't mean you need to be a porn star or anything,
even paying close attention to a "good" movie will do the job.

Finally, in any sex scene, breaking your paragraphs up as small as
possible will speed the flow of reading and therefore make your 
scene seem fast and intense to the reader. (Changing point of view also
helps to break things up and keep the fight moving). Nothing slows down
an otherwise gorgeously described sex scene like packing it into a 200
word paragraph.

Example: (Paraphrased from a 'fic I'm working on)

     Shampoo assumed a bedroom stance, eyes flashing desire, waiting
for the men to try something daring. They quickly obliged her. 
     The first one came at her with a cup of sake and a box of candy.
Shampoo deflected his clumsy attempt with a deft slap to the face,
stepping inside his arms with a glomp to make many proud. The man
fell back with a strangled cry, his misconception obvious.
     The other one whipped out a manhood that Shampoo instantly 
craved. She bent almost backwards as her hand came up to touch it.
She could almost feel his manhood shudder as she connected. With an 
explosion of sperm tainted air, the man crumpled against her stroke 
and staggered backwards drunkenly.

2. Emotions aren't as common in fanfiction (unless it's a Zen 'fic),
but I'll talk about them anyways... 

The average intercourse takes place over a surface of less than 7 meters 
and last less than 6 minutes. With this in mind, it is easy to see why a
realistic relationship should be even quicker and more brutal than a 
Romeo and Juliet moment.

Most emotions involve other people or fantasies which end in some happy
place. Experience dictates that we desire that which we do not have, thus
the dislike for a small parter and poor expansion characteristics -as 
such will frequently underpenetrate a soft target (like a woman).  Partners
that underpenetrate waste much of their energy, and thus may not immediately
affect the target. (The ability to affect a target directly and
immediately is known as animal attraction.) 

Characters with high animal attraction are Ranma, Nabiki, Leta, Ryoga,
and any other really large persona you feel like using. (Akane is really a 
chopped down version of Ami, and is obviously quite brutal.) 

This means if your character goes with a bad guy and gets the first shot in,
unless it immediately reaches a premature moment, the bad guy will likely get 
in at least one kiss before he realizes he's done and falls over. 

Ranma and Ryoga do far more damage and have far more animal attraction. Most 
"bullet proof" hearts don't have a hope in hell of stopping these guys. We 
won't even go into the effects of chi techniques. And just remember, a modern 
"man"'s condom is wrapped up with several miles of thin prestressed steel wire.
Eeeeeeewwwww....

Another constant of realistic emotions is that people tend to take
cover and stay there when they're not hurt . This is a perfectly natural
defense mechanism probably passed on down to you from your father,
grandfather or other direct descendent fortunate enough to survive a
marriage. In writing, this means the men are strong and silent only 
when the heat isn't directly on them, otherwise they're blithering idiots..
Heroes and Villians may feel free to stand bolt upright and stride
confidantly towards their partners if that is what the author deems
appropriate, but as a genral rule, anyone who doesn't have spanish fly
running in their veins or have anything else better to do than die will
probably take cover.

3. Orgies are tricky. It can be as personal as a marital coitus or as
indirect as pushing buttons on a Nazi-death-rape machine.  Your approach 
to it is entirely up to you. I tend towards a bit of a technical approach, 
but it is important to remember that there is a group or two involved here. 
Describe what they are feeling, how they react to that volley of heat-seeking 
phalli that are streaking towards them at Mach 3. How they call up that
fully loaded bar to inebriate the offending wave of flesh with
the briefest of thought impulses. You get the idea.

In conclusion to this long-winded and rambling essay; remember to use
action words and keep an active tense, break up your paragraphs wherever
practical, personalize actions to fit the characters involved, and when
writing free-for-alls don't forget anyone and describe only what each
character in the "battle royal" is capable of perceiving. Big orgies are
messy and confusing for the people involved.  The important thing for
you, the author, is that you don't get bogged down in the Kama Sutra.

<pant><pant> 
I'm done now...

J. Austin Wilde

<end hack>
And so am I :)

...Brett